The present disclosure relates to a commutator.
There exists a commutator to be provided in an electric motor that has a plurality of segments that are formed on an outer peripheral surface. A riser is formed on one end in an axial direction of each segment. In an armature of an electric motor, the commutator is integrally externally fitted to a shaft. A winding that forms a coil that is wound around the armature is laid around the risers, whereby the segments and the coil are electrically connected to each other.
The commutator is formed such that, on an inner periphery of a cylindrical body that is formed of a conductive plate member and on which latching claws are formed, an insulating resin part is integrally molded. Thereafter, the outer peripheral surface of the cylindrical body is cut in order to form a plurality of segments on the outer peripheral surface. The commutator is required to have high circularity (shaft alignment) in view of motor performance and durability of the electric motor.
In order to have high circularity for motor performance and durability of the electric motor, a proposed cylindrical body that has latching claws that are formed on its peripheral surface is formed such that a long plate member is bent and formed into a cylindrical body. The cylindrical body is also formed by forcibly inserting a columnar mold that has claw forming grooves that are formed on its outer periphery into the cylindrical body (see Japanese Published Unexamined Patent Application No. 2003-231132 for example).